Caution - Users/Readers are to be Cautioned that some of the audio file examples and experiments contained in this Thread. Can cause Damage to either your Hearing or your Speakers if conducted incorrectly. If you don’t completely understand exactly what is being done in these tests use reasonable caution and keep volume/gain levels very low. Some of these test will destroy your Hearing and/or Speakers or both! (Added by Moderator)
A somewhat heated discussion arose in a diff thread about the missing fundamental of a 15kHz signal. On short: considering that its 30/45/60/..kHz HDs are inaudible, will 15 kHz be audible as a missingF ?
There are many pro & contra arguments but a clear, direct test is missing: i.e. generate a 30/45/60/..kHz combo-signal and see if its 15kHz missingF can be heard.
I offered to donate €50 to ASR if someone does a (credible) test. And increase that to €100 is someone figures out an easy test that can be done by AverageAsrJoe. Or even by me (details in the spoiler below).
I'll pay that if my assumption (missingF still audible) turns out to be wrong. @Julf already offered to take the other side of the 'bet. Any other amateurs?
And an even bigger question: anyone who can/want to actually do the test?
P.S.
a missingF test for 10kHz should be easier. I'll take that too.
A somewhat heated discussion arose in a diff thread about the missing fundamental of a 15kHz signal. On short: considering that its 30/45/60/..kHz HDs are inaudible, will 15 kHz be audible as a missingF ?
There are many pro & contra arguments but a clear, direct test is missing: i.e. generate a 30/45/60/..kHz combo-signal and see if its 15kHz missingF can be heard.
I offered to donate €50 to ASR if someone does a (credible) test. And increase that to €100 is someone figures out an easy test that can be done by AverageAsrJoe. Or even by me (details in the spoiler below).
I'll pay that if my assumption (missingF still audible) turns out to be wrong. @Julf already offered to take the other side of the 'bet. Any other amateurs?
And an even bigger question: anyone who can/want to actually do the test?
Sounds like a pretty complex test to me:
- transducers that can play 50+kHz are needed. (I don't have any). @Julf suggested a $8 Piezo Tweeter. Only goes to 27kHz but maybe someone knows a better one (and ~same as cheap).
- an amp that can reliably play 50+kHz is needed. (I might have some but no way to reliably prove/check).
- @HarmonicTHD's suggested using Distort to generate the test signal. Seems viable, an 192kHz sample rate is needed to avoid the DAC filter (thanks @Sokel).
- Using an analog signal generator would be my preferred way. (I don't have any but the Distort-way should be good enough).
- An oscilloscope would be very nice as a control device. (I don't have any either).
- Missing piece of info: how many HDs do you need to hear/test a missingF? Is 3 of them enough?
- Let's say that one hears a by-product of the 30/45/60kHz combo signal:
- How do they prove that it was heard?
- How do they prove that it was exactly the 15 kHz pitch?
- How do they prove that it's the missing 15 kHz fundamental and not some IMD product?
P.S.
a missingF test for 10kHz should be easier. I'll take that too.
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